Pesticidal formulations

ABSTRACT

A formulation suitable for spraying or for dilution with water to form a sprayable preparation, the formulation comprising an active ingredient, optionally a carrier or solvent for the active ingredient, an emulsifier and an evaporation retardant, characterized in that the formulation satisfies formula ##EQU1## where L is less than or equal to 15, A=700376, B=-1.51, C=0.8472, M oil  is the weighted average relative molar mass of the oil phase M retardant  is the weighted average relative molar mass of the retardant, and X=(M oil ) 1.8/Y, where Y is the molar solubility ration of the formulation, defined as the minimum number of moles of the oil phase which will dissolve the retardant, divided by the number of moles of retardant, provided that, in the formula above, any solvent which has no liquid phase at 27° C. at atmospheric pressure is excluded. The formulation may comprise a pesticide or herbicide. The action of the evaporation retardant is improved.

PRIOR APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 924,044, filed Aug. 24, 1992, now abandoned and of U.S. patentapplication Ser. No. 979,452, filed Nov. 22, 1992, which is acontinuation of U.S. patent application Ser. No. 845,804, filed Mar. 9,1992, which is a continuation of U.S. patent application Ser. No.438,399 filed Dec. 27, 1989 all abandoned.

SPRAY FORMULATIONS

The present invention relates to spray formulations, especiallypesticidal formulations of the sort which may be diluted with water toform a sprayable preparation, for example a pressure pack ("aerosol")preparation or a spray, particularly an ultra low volume (ULV) spray fordomestic, horticultural, agricultural, environmental or industrial use.

Water-based sprays are advantageous because they cost less thanoil-based sprays and are often less toxic to mammals. However,particularly when the ambient temperature is high, the water in thespray droplets evaporates and the droplets become smaller and drift morereadily from the area being sprayed. The size of the droplets isfrequently specially chosen to suit the application, for example tomaximize droplet adherence to flying insects or adherence to plantFoliage, to increase bio-availability, or to control the size of thearea being sprayed and the delivery rate per square meter; such care ispointless if the spray droplets change size, possibly unpredictably,following spraying.

GB-A-2 095 109 discloses improved water-dilutable formulationscomprising a long-chain fatty alkanol which retards the evaporation ofthe water from the drops of the spray.

We have now found that still better evaporation retardation can beachieved if the Formulation satisfies the following Formula: ##EQU2##where L is less than or equal to 15, A=700376, B=-1.5, C=0.8472

M_(oil) is the weighted average relative molar mass of the oil phase

M_(retardant) is the average molar mass of the retardant, and ##EQU3##where Y is the molar solubility ratio of the formulation, defined as theminimum number of moles of oil phase which will dissolve the retardant,divided by the number of moles of retardant,

provided that, in the Formula above, any solvent which has no liquidphase at 27° C. at atmospheric pressure is excluded.

For the avoidance of doubt, and to clarify any ambiguities which mayarise in the printing or copying of this specification, it is to benoted that the relational symbol in the Formula is "less than or equalto" , "Exp" means the exponential of what follows in brackets, "in"means the natural logarithm, i.e. log_(e), L is divided by 4 , X israised to the power B, B is a negative value (minus 1.51) and, in thedefinition of X, M_(oil) is raised to the power 1.8.

The "oil phase" is the liquid non-aqueous phase and will comprise one ormore of the active ingredient, the solvent therefor and the emulsifier.

Preferably L, which is related to the evaporation rate from the sprayeddroplets, is less than 12, 10, or 8 and is most preferably less than 5.A distilled water spray has an "L" value of about 26, and mostconventional diluted formulations have a value of about 22-30. In theformulations of the invention, "L" can be set at a desired value inorder to calculate the required ratios of the ingredients. "L" can alsobe measured for a given formulation by the method described below.

The evaporation retardant may be any film-forming compound, preferablyan alkanol. It is preferably a primary alcohol: preferably with no morethan one or two side substitutions selected from methyl, ethyl,trifluoromethyl and halo (e.g. fluoro or chloro), with suchsubstitutions preferably remote from the alcohol group (preferably atleast 7 carbon atoms away from the hydroxyl group), and preferably thealkanol is not substituted at all: preferably C₁₆₋₂₀ ; preferablysaturated: and preferably a solid at 27° Octadecan-1-ol and,particularly, hexadecan-1-ol are preferred. Hexadecan-1-ol (also knownas cetyl alcohol) is usually available commercially as a mixture with aminor proportion of octadecan-1-ol (stearyl alcohol) and such"cetostearyl alcohol" is quite satisfactory. Heptadecan-1-ol performsadequately but is much more expensive. Other highly effectivefilm-forming agents include 1-hexadecylamine, 1-heptadecylamine and1-octadecylamine. Less preferred film-forming agents includehexadecan-2-ol, 1,2-hexadecandiol, methyl stearate, stearyl acetate,methyl palmirate and 1,2-octadecandiol. N-alkoxyalkanols may be used,for example CH₃ (CH₂)₂₁ OC₂ H₄ OH, CH₃ (CH₂)₂₁ OC₃ H₆ OH, CH₃ (CH₂)₁₇OC₂ H₄ OH or CH₃ (CH₂)₁₅ OC₂ H₄ OH, as may oxyethylene-docosanol andmixtures of any of the said evaporation retardants.

The emulsifier may be any suitable compound or mixture of compounds.Cationic emulsifiers can be used, but they tend to irritate the users'eyes. Anionic emulsifiers such as calcium dodecyl benzene sulphate(CDBS) or sodium di-isopropyl naphthalene sulphonate (SDNS) can also beused, but these are not as effective at stabilizing the emulsion.Preferably, the emulsifier is a non-ionic compound, or mixture ofnon-ionic compounds, having an HLB (hydrophilic/lipophilic balance) of8-18. Suitable compounds include polyoxyethylene stearyl ethers(PSE),polyoxyethylene monolaurates(PEM), polyoxyethylene mono-oleates (PMO),sorbitan mono-oleate (SMO), nonylphenol ethoxylate (NPE), polyethyleneglycol (PEG) and blends of oleyl ethoxylate (10 mole) and PEG20 glyceryloleate (OE/PGO).

These emulsifiers are available as follows:

    ______________________________________                                        Abbrev  Trade name       Supplier                                             ______________________________________                                        OE/PGO  Tegoplant EM11   Th. Goldschmidt Ltd                                  PSE     Brij 72, Brij 76, Brij 78                                                                      ICI Speciality                                                                Chemicals                                            PEM     Tween 20         ICI Speciality                                                                Chemicals                                            SMO     Span 80          ICI Speciality                                                                Chemicals                                            PMO     Tween 80         ICI Speciality                                                                Chemicals                                            NPE     Ethylan KEO, 55, BV                                                                            Lankro Chemicals                                                              Limited                                              CDBS    Arylan CA        Lankro Chemicals                                                              Limited                                              SDN     Aerosol OS       Cyanamid GB Ltd                                      ______________________________________                                    

The solvent, at least for an oil-soluble active ingredient, preferablyhas a low relative molecular mass, namely less than about 200. Suitablecompounds include lower alkyl esters, lower ketones, lower alkanols andlower alkanes, the term "lower" meaning C₁₋₁₀, preferably C₁₋₅.

Particular solvents include the following, all available from ExxonChemicals Limited. "Solvesso 150"--An aromatic hydrocarbon solvent (C9to C11) with a distillation range 190° to 210° C. "Solvesso 200"--Anaromatic hydrocarbon solvent (C10 to C12) with a distillation range 226°to 290° C. "Exxate 700"--Heptyl acetate 99% pure, or odorlesskerosene--A mixture of high boiling non-aromatic hydrocarbons consistingof paraffins and naphthenes with a distillation range of 180° to 270° C.

The formulation may comprise more than one active ingredient (optionallywith a synergist or potentiator, which is regarded as an activeingredient for the purpose of the Formula above, more than one solvent,more than one emulsifier and/or more than one retardant, together withother ingredients such as perfumes, dyes, anti-foam agents, solidsespecially to form wettable powders) and thickeners. Some compounds,such as butane, propane and dichlorodifluoromethane and carbon dioxideare highly volatile and are used as propellants in pressure packformations. Although sometimes acting as solvents for particular activeingredient, they almost instantly evaporate from the drops when sprayedand are thus excluded from the calculations in the Formula above. Suchsolvent/propellants are those which have no liquid phase at 27° C. atatmospheric pressure.

In a modification of the formulations of the invention, particularlypesticidal formulations which contain two incompatible pesticides, areuseful. It has been found that an anhydrous formulation of a pesticide,i.e. one which does not contain an aqueous phase, may be formulated witha second immiscible phase which contains a second pesticide. This hasthe advantage that incompatible pesticides may be incorporated in thesame formulation.

Accordingly to this modification, the invention provides a two-phaseformulation, the first phase of which comprises a first activeingredient, a stabilizer, and optionally an emulsifier or wetting ordispersing agent, and a carrier or solvent for the active ingredient;and a second phase immiscible with the first phase which comprises asecond active ingredient and optionally an emulsifier or wetting ordispersing agent and a carrier or solvent for the second activeingredient.

Normally, the first active ingredient is dissolved or dispersed into thefirst phase but when the active ingredient is a liquid, a solvent is notalways required. The second phase which is immiscible with the firstphase contains the second active ingredient either dissolved ordispersed in the second phase. Preferably, the first phase is a waterimmiscible phase and the second phase is a water phase.

The first and second active ingredients are preferably physically and/orchemically incompatible when contained in a single phase, i.e. thepresence of one of the actives in a formulation normally affectsadversely the stability or utility of the other active. In addition, theactive ingredient in the first phase may be one which has properties,for example irritancy or noxious vapor, which may be avoided byformulating it according to the present invention. Thus, it may havebeen possible previously to prepare stable but irritant formulations ofthe active ingredients; formulations of the invention may avoid suchirritancy.

By active ingredient we mean both non-biologically and biologicallyactive compounds. For example, the active ingredients may be selectedfrom insecticides, acaricides, herbicides, fungicides, insect and plantgrowth regulators, pheromones, insect behavior modifiers, biologicalcontrol agents (e.g. viruses, bacteria and eggs of parasites), dyes,perfumes, flavors, bactericides, lubricants, medicaments, foodsupplements, paints, polishes, lacquers (including hair lacquer),textile treatments (including sizes), or other active ingredients whichare limited in their use by their incompatibility with other activeingredients. Examples of incompatible actives include combinations ofpesticides selected from arthropodicides (insecticides, acaricides),herbicides, fungicides or insect and plant growth regulators. Examplesof incompatible pesticides are the pyrethroids and organophosphateinsecticides, the pyrethroid and formamidine insecticides,α-cyano-pyrethroid insecticides and thiazole anthelmintics, andpyrethroids and tributyl tin fungicides. Examples of incompatiblepesticides are the pyrethroids and organophosphate insecticides, thepyrethroid and formamidine insecticides, α-cyano-pyrethroid insecticidesand thiazole anthelmintics, and pyrethroids and tributyl tin fungicides.

Examples of pyrethroid insecticides include those of the formula (I)##STR1## where R is ##STR2## and n is 0 or 1,

R¹ is halo CF₃ or CHF₂ O, R² is hydrogen or halo, and Z and Z¹ are eachindependently selected from halo, CF₃ and methyl, X is hydrogen or halo,and X is H, CN or C═CH ##STR3## Examples of pyrethroids are3-phenoxybenzyl-(1RS)-cis,trans-3-(2,2-dichlorovinyl-2,2-di-methyl-cyclopropane-1-carboxylate(permethrin),(RS)-α-cyano-3-phenoxybenzyl-(1RS)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylate(cypermethrin) and its individual isomers such as the (1RS) cis isomer(alphamethrin),(S)-α-cyano-3-phenoxybenzyl-(IR)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylate (deltamethrin), or a reaction mixturecomprising two enantiomeric pairs in approximately ratio 2:3(S)-α-cyano-3-phenoxybenzyl-(IR)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylateand (R)-α-cyano-3-phenoxybenzyl(IS)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate with(S)-α-=cyano-3-phenoxybenzyl(IR)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate and(R)-α-cyano-3-phenoxybenzyl(IS)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate(beta-cypermethrin),(RS)-α-cyano-3-phenoxybenzyl-(Z)-(IRS)-cis-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate (cyhalothrin) and amixture of its (S)(Z)-(IR)-cis and (R)(Z)-(IS)-cis-isomers;(RS)-α-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate(fenvalerate) and the single (S), (S) isomer (esfenvalerate)(RS)-α-cyano-3-phenoxybenzyl (S)-2-(4-difluoromethoxyphenyl)-3-methylbutyrate (flucythinate), (RS)-α-cyano-3-phenoxybenzyl N(2-chloro-α,α,α-trifluoro-p-tolyl)-D-valinate(fluvalinate),(RS)-α-cyano-4-fluoro-3-phenoxybenzyl(IRS)-cis-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate (cyfluthrin), (RS)-α-cyano-4-fluoro-3-phenoxybenzyl(IRS)-cis-trans-3-(2-chloro-2(4-chlorophenyl)vinyl)-2,,2-dimethylcyclopropanecarboxylate(flumethrin),2-methylbiphenyl-3-yl-methyl(Z)-(IRS,3RS)-3RS)-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)2,2-dimethylcyclopropanecarboxylate (Bifenthrin); the allethrins, for example(1RS)-3-allyl-2-methyl-4-oxocylopent-2-enyl(1R,3R)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate(bioallethrin), (1S)-allyl-2-methyl-4-oxocyclopent-2-enyl(1R,3R)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate(S-bi-oallethrin), and mixtures of allethrin isomers (esbiothrin); theresmethrins, for example 5-benzyl-3-furylmethyl(IRS, 3RS; IRS,3SR)-2,2-dimethyl-3-(2-methyl-prop-1-enyl)cyclopropanecarboxylate(resmethrin) and 5-benzyl-3-furylmethyl(1R,3R)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate(bioresmethrin).

Examples of organophosphate insecticides are:

0,0-dimethyl-0-3,5,6-trichloro-2-pyridylphosphorothioate(Chloropyri-fos-methyl)

Examples of formamidine insecticides include N-methylbis(2,4-xylylaminomethyl)amine (Amitraz). Examples of thiazoleanthelmintics include2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b]thiazole(levamisole).

Examples of fungicides include tributyl tin oxide.

Particularly preferred examples of incompatible actives in theformulations of the present invention include deltamethrin andchlorpyrifos methyl in an aqueous system.

The first phase is preferably dispersed within the second phase. Thestabilizer forms a barrier at the interface between the dispersed firstphase and the second phase. The stabilizer is preferably a film-formingalkanol e.g. an alkanol which can act as an evaporation retardant in anaqueous spray system as described in European Patent Specification331474. It is preferably a primary alcohol; preferably with no more thanone or two side substitutions selected from methyl, ethyl,trifluoromethyl and halo (e.g. fluoro or chloro), with suchsubstitutions preferably remote from the alcohol group (preferably atleast 7 carbon atoms away from the hydroxyl group), and preferably thealkanol is not substituted at all; preferably C₁₆₋₂₀ ; preferablysaturated; and preferably a solid at 27° C., Octadecan-1-ol and,particularly, hexadecan-1-ol are preferred. Hexadecan-1-ol (also knownas cetyl alcohol) is usually available commercially as a mixture with aminor proportion of octadecan-1-ol (stearyl alcohol) and such"cetostearyl alcohol" is quite satisfactory. Heptadecan-1-ol performsadequately but is much more expensive. Other highly effectivefilm-forming agents include 1-hexadecylamine, 1-heptadecylamine and1-octadecylamine. Less preferred film-forming agents includehexadecan-2-ol, 1,2-hexadecandiol, methyl stearate, stearyl acetate,methyl palmirate and 1,2-octadecandiol. N-alkoxyalkanols may be used,for example CH₃ (CH₂)₂₁ OC₂ H₄ OH, CH₃ (CH₂)₂₁ OC₃ H₆ OH, CH₃ (CH₂)_(CH)₁₇ OC₂ H₄ OH or CH₃ (CH₂)₁₅ OC₂ H₄ OH, as may oxyethylene-docosanol andmixtures of any of the said film-forming compounds.

The first phase may comprise more than one active ingredient (optionallywith a synergist or potentiator, which is regarded as an activeingredient for the purpose of the Formula below), more than one solvent,more than one emulsifier and/or more than one stabilizer, together withother ingredients such as perfumes and dyes. M_(oil), the averagemolecular weight of the oil phase, is the weight average, i.e. takinginto account the relative proportions of the ingredients.

The value "Y", namely the molar solubility ratio of the formulation, maybe derived empirically by making up at 40° C. a series of mixtures withdifferent ratios of oil phase to alkanol, allowing the mixtures to coolto 27° C., leaving the cool mixtures for at least 48 hours at 27° C.,and determining the amount, in moles, of the oil phase which is neededto dissolve completely a given amount of retardant, in moles. The formeris then divided by the latter to give Y.

The formulations of the invention may be (i) single phase substantiallyanhydrous formulations, or (ii) emulsions comprising water. In aformulation of type (ii), some of the active ingredient, solvent oremulsifier components may partition into the aqueous phase, in whichcase such components are deemed not to be part of the oil phase in theFormula above. Examples of water-miscible solvents include ethanol,propanol, ethylene glycol and propylene glycol. It has been found thatpartially water-miscible components may be treated as being whollywater-miscible and hence excluded from the oil phase in thecalculations.

When the formulation of the invention is diluted to give a sprayablepreparation, the molar ratio of water to retardant should preferably notexceed about 9000, and preferably not exceed 8000, 7000 or 6000. It isperfectly possible to prepare a more dilute solution, but all that willhappen is that the retardant will be unable to form a film over theentire surface of the droplets, and the water will evaporate until thereis a sufficient concentration of the retardant to form a complete filmwhich will then retard further evaporation. Thus, the droplet size isless controllable and, in addition, a larger volume of solution must bestored and pumped, which is inefficient.

The active ingredient of the one phase compositions may be aninsecticide, acaricide, herbicide, fungicide, plant growth regulator,insect behavior modifier, biological control agent (e.g. viruses,bacteria and eggs of parasites), dye, perfume, bactericide, lubricant,medicament, paint, polish, lacquer (including hair lacquer), textiletreatment (including sizes), or any other compound to be sprayed in awater-based formulation. Sprays in accordance with the invention areparticularly suitable for spraying buildings, residential or commercialareas and insect breeding grounds (such as stamps and other tracts ofwater) with insecticide and for spraying crops with herbicides,insecticides, fungicides and plant growth regulators.

Suitable pesticides including pyrethroids (such as permethrin,deltamethrin, cypermethrin (including alphamethrin, the allethrins,fenvalerate and cyfluthrin), organophosphates (such as ethion,chlorfenvinphos, chlorpyrifos (methyl) or coumaphos), carbamates,organochlorines (such as DDT, dieldrin, dicofol, chlorpropylate ortetradifon), lipid amides, bicyclooctanes and dithianes. Suitableherbicides include glyphosate.

The sprays may be delivered by pumping through a nozzle, especially asonic nozzle, by pumping over an ultrasonic nebulizer, or via a spinningdisc. The droplets may be electro-statically charged, if desired.

As well as the uses discussed above, at least some of the formulationsof the invention can be used to form a larvicidal Film over a lake.

To determine whether a given formulation satisfies the Formula givenabove, the following procedure may be adopted. If the formulation is anemulsion, the emulsion should first be "broken" by extraction of theconcentrate with a suitable solvent such as ether. The ingredients arethen analyzed by suitable quantitative and qualitative analyticalmethods. If not already known, the miscibility of each component withwater is tested: if the component is water-miscible in the conditions ofthe Formulation, it is excluded From the calculations. The solubility ofthe evaporation retardant in the oil phase (excluding water-misciblecomponents) is determined. The parameters are then operated on in themanner defined in the Formula to see whether the (mass of oilphase)/(mass of retardant) ratio is less than or equal to the figure onthe right hand side of the Formula. This procedure is explained belowwith specific reference to the Examples.

In a preferred aspect, the first phase of the two phase formulationsatisfies the formula: ##EQU4## where L is less than or equal to 15,A=700376, B=-1.51, C=0.8472 M_(oil) is the weighted average relativemolar mass of the oil phase M_(stabilizer) is the average molar mass ofthe stabilizer, and ##EQU5## where Y is the molar solubility ratio ofthe formulation, defined as the minimum number of moles of oil phasewhich will dissolve the stabilizer, divided by the number of moles ofstabilizer, provided that, in the Formula above, any solvent which hasno liquid phase at 27° C. at atmospheric pressure is excluded.

The "oil phase" is the liquid non aqueous phase and will comprise one ormore of the active ingredient, the solvent therefor and in some casesthe emulsifier.

Preferably L is less than 12, 10, or 8 and is most preferably less than5. A distilled water spray has an "L" value of about 26, and mostconventional diluted formulations have a value of about 22-30.

In the two phase formulations of the invention, "L" can be set at adesired value in order to calculate the required ratios of theingredients.

Preferred film-forming compounds include C₁₆₋₂₀ saturated alkanols suchas hexadecan-1-ol and C₁₆₋₁₈ saturated amines. Preferred emulsifiers andsolvents for the first phase are as described hereinbefore for EuropeanPatent Specification 331474, which is incorporated herein by reference.

The use of the two phase formulations of the invention will be dependentupon the nature of the active ingredients included within theformulation but the formulations will commonly be used to controlpesticidal infestations such as insect, acarine or helminth or microbialinfestations. The application rate of the active ingredients willcorrespond to the application rates of these actives when appliedconventionally for that particular use.

A preferred formulation of the present invention contains 20% ofchloropyrifos methyl and 1% of deltamethrin, cetyl alcohol being thestabilizer. This formulation is useful for the treatment of stored cropssuch as grain, in particular, against insect pests, of the ordersColeoptera (e.g. Anobium, Ceutorhynchus, Rhynchophorus, Cosmopolites,Lissorhoptrus, Meligethes, Hypothenemus, Hylesinus, Acalymma, Lema,Psylliodes, Leptinotarsa, Gonocephalum, Agriotes, Dermolepida,Heteronychus, Phaedon, Tribolium, Sitophilus, Oryzaephilus, Rhyzopertha,Prostephanus, Cryptoletes, Trogoderma, Typheae, Diabrotica, Anthonomusor Anthrenus spp.), Lepidoptera (e.g. Ephestia, Mamestra, Earias,Pectinophora, Ostrinia, Trichoplusia, Pieris, Plodia, Sitotroga,Corcyra, Laphygma, Agrotis, Amathes, Wiseana, Tryporysa, Diatrae,Sporganothis, Cydia, Archips, Plutella, Chilo, Heliothis, Spodoptera orTineola spp.), Diptera (e.g. Musca, Aedes, Anopheles, Culex, Glossina,Simulium, Stomoxys, Haematobia, Tabanus, Hydrotaea, Lucilia, Chrysomla,Callitroga, Dermatobia, Gasterophilus, Hypoderma, Hylemyia, Atherigona,Chlorops, Phytomyza, Ceratitis, Liriomyza and Melopbagus spp.),Phthiraptera (Malophaga e.g. Damalina spp. and Anoplura e.g. Linognathusand Haematopinus spp.), Hemiptera (e.g. Aphis, Bemisia, Photodon,Aeneolamia, Empoasca, Parkinsiella, Pyrilla, Aonidiella, coccus,Pseudococus, Helopeltis, Lygus, Dysdercus, Oxycarenus, Nezara,Aleurodes, Triatoma, Psylla, Mysus, Megourn, Pbylloxera, Adelyes,Niloparvata, Nephrotetix or Cimex spp.), Orthoptera (e.g. Locusta,Gryllus, Schistocerca or Acheta spp.), Dictyoptera (e.g. Blattella,Periplaneta or Blatta spp.) Hymenoptera (e.g. Athalia, Cephus, Atta,Solenopsls or Monomorium spp.), Isoptera (e.g. Odontotermes andReticulitermes spp.), Siphonaptera (e.g. Ctencephalides or Pulex spp.),Thysanura (e.g. Lepisma spp.), Dermaptera (e.g. Forficula spp.),Pscoptera (e.g. Peripsocus spp.) and Thysanoptera (e.g. Thrips tabaci),.Acarine pests include ticks, e.g. members of the genera Boophilus,Ornithodorus, Rhipicephalus, Amblyomma, Hyalomma, Ixodes, Haemaphysalis,Dermacentor and Anocentor, and mites and manges such as Acarus,Tyrophagus, Glycyphagus, Tetranychus, Psoroptes, Notoednes, Sarcoptes,Psorergates, Chorioptes, Eutrombicula, Demodex, Panonycbus, Bryobia,Eriophyes, Blaniulus, Polyphagotarsonemus, Scutigerella, and Oniscusspp. and Periplaneta, Blatta, Blattella and Lapisma.

The two phase formulations may be prepared as follows:

1) The first active is dissolved in a solvent to form, or is itself, thefirst phase.

2) The stabilizer is dissolved into the first phase.

3) The second active ingredient is dispersed in part of the secondphase.

4) The surfactants are dispersed either into the first phase or into thepart of the second phase containing the second active ingredient.

5) The first phase is then dispersed into that part of the second phasethat does not contain the second active ingredient.

6) The remainder of the second phase containing the second activeingredient is mixed with the mixture of the first phase and the otherpart of the second phase. Step (6) is not carried out under high sheerconditions. Therefore the second portion of the second phase simplycombines with the first portion of the second phase and the end resultis a first-phase-in-second-phase dispersion or emulsion.

In the following examples, there are described several preferredembodiments to illustrate the invention. However, it should beunderstood that the invention is not intended to be limited to thespecific embodiments.

EXAMPLE 1A

A ULV insecticide formulation was made up of the following components.

    ______________________________________                                                       % mass/mass                                                                            Rel. molar mass                                       ______________________________________                                        Oil phase                                                                     Permethrin       10.32      391                                               S-Bioallethrin   1.51       302                                               Piperonyl Butoxide                                                                             11.32      338                                               Odorless kerosene                                                                              9.30       170                                               Hexadecan-1-ol   3.00       242                                               Emulsifiers                                                                   Tegoplant EM11   0.75                                                         Brij 76          0.24                                                         Tween 20         0.01                                                         Aqueous phase                                                                 Water            63.45      18                                                Silcolapse 5000  0.10                                                         "Silcolapse" is a Regd. T.M.                                                  ______________________________________                                    

The concentrate was diluted in 1+9 parts with water for application. Theaverage relative molar mass of oil phase=271 and the molar solubilityratio (moles oil phase/moles alkanol)=9.4.

Model prediction: ratio (mass oil phase/mass of alkanol) of aformulation within the scope of the invention:

Maximum ratio with an evaporation rate (L) of 15=27.5 with L of 10=17and with L of 5=7. Hence, the invention encompasses all suchformulations where the mass ratio for this solvent/pesticide mixture tohexadecan-1-ol is less than or equal to 27.

The above formulation has the ratio (mass of oil phase/mass ofalkanol)=10.8 and the ratio (moles water/moles of alkanol)=4318 whendiluted. Observed average evaporation rate (L)=3.8.

EXAMPLE 1B

A ULV insecticide spray

    ______________________________________                                                       % mass/mass                                                                            Rel. molar mass                                       ______________________________________                                        Oil phase                                                                     Permethrin       10.87      391                                               S-Bioallethrin   0.15       302                                               Piperonyl Butoxide                                                                             11.07      338                                               Odorless kerosene                                                                              9.30       170                                               Hexadecan-1-ol   3.00       242                                               Emulsifiers                                                                   Tegoplant EM11   0.75                                                         Brij 76          0.24                                                         Tween 20         0.01                                                         Aqueous phase                                                                 Water            64.51      18                                                Silcolapse 5000  0.10                                                         "Silcolapse" is a Regd. T.M.                                                  ______________________________________                                    

EXAMPLE 2A

A ULV insecticide formulation

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Delamethrin       1.0        505                                              Heptyl acetate (Exxate 700)                                                                     30.0       158                                              [Exxon Chemicals]                                                             Hexadecan-1-ol    5.0        242                                              Emulsifier                                                                    Tegoplant EM11    1.0        800                                              Aqueous phase                                                                 Silcolapse 5000 (anti foam agent)                                                               0.1        --                                               Water             62.9       18                                               ______________________________________                                    

The concentrate was diluted in 1+19 parts with water for sprayapplication and the parameters for these and the subsequent Examples aregiven in Table 1.

EXAMPLE 3

A ULV insecticide formulation

    ______________________________________                                                       % mass/mass                                                                            Rel. molar mass                                       ______________________________________                                        Oil phase                                                                     Alpha cypermethrin                                                                             2.0        416                                               Heptyl acetate (Exxate 700)                                                                    30.0       158                                               [Exxon Chemicals]                                                             Hexadecan-1-ol   7.0        242                                               Emulsifier                                                                    Tegoplant EM11   0.1        800                                               Aqueous phase                                                                 Water            60.0       18                                                Observed average evaporation rate = 4.5                                       ______________________________________                                    

EXAMPLE 4

A ULV insecticide formulation

    ______________________________________                                                      % mass/mass                                                                            Rel. molar mass                                        ______________________________________                                        Oil phase                                                                     Permethrin      25.0       391                                                4-methylpentan-2-one                                                                          32.0       100                                                Hexadecan-1-ol  6.0        242                                                Propan-2-ol     32.0       -- *                                               Emulsifiers                                                                   Tween 80        3.6                                                           Span 80         1.4                                                           ______________________________________                                         * assumed to partition mostly into the aqueous phase on dilution as it wa     watermiscible. This formulation was found to be particularly effective.  

EXAMPLE 4B

A ULV insecticide spray

    ______________________________________                                                    % mass/mass                                                                            Rel. molar mass                                          ______________________________________                                        Oil phase                                                                     Permethrin    25.0       391                                                  Hexadecan-1-ol                                                                              6.0        242                                                  Emulsifiers                                                                   PMO           3.6                                                             SMO           1.4                                                             Aqueous phase none                                                            ______________________________________                                    

EXAMPLE 5

A pressure packed insecticide formulation

    ______________________________________                                                    % mass/mass                                                                            Rel. molar mass                                          ______________________________________                                        Oil phase                                                                     Bioallethrin  0.315      302                                                  Permethrin    0.038      391                                                  Odorless kerosene                                                                           8.3        170                                                  Butane        40.0       -- *                                                 Hexadecan-1-ol                                                                              1.0        242                                                  Emulsifier                                                                    Tegoplant EM11                                                                              1.0        800                                                  Aqueous phase                                                                 Water         50.347     18                                                   ______________________________________                                         * excluded due to its volatility (vapor at normal temperatures and            pressures)                                                               

EXAMPLE 6

A ULV insecticide formulation

    ______________________________________                                                      % mass/mass                                                                            Rel. molar mass                                        ______________________________________                                        Oil phase                                                                     Pyrethrins (PY) 2.0        350                                                Solvent in PY extract                                                                         6.0        150                                                Piperonyl Butoxide                                                                            16.0       338                                                Octadecan-1-ol  2.5        270                                                Emulsifier                                                                    Tegoplant EM11  1.0        800                                                Aqueous phase                                                                 Water           72.4        18                                                Silcolapse 5000 0.1        --                                                 ______________________________________                                    

Ready use concentrate (no further dilution required).

EXAMPLE 7

A ULV insecticide formulation

    ______________________________________                                                     % mass/mass                                                                            Rel. molar mass                                         ______________________________________                                        Oil phase                                                                     Chlorpyrifos-methyl                                                                          20.0       323.0                                               Solvesso 150   20.0       144.0                                               [Exxon Chemicals]                                                             Hexadecan-1-ol 3.0        242                                                 Emulsifier                                                                    Tegoplant EM11 2.0        --                                                  Aqueous phase                                                                 Water          54.9       18                                                  Silcolapse 5000                                                                              0.1        --                                                  ______________________________________                                    

EXAMPLE 8

A wettable powder formulation

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Inorganic carrier                                                             Celite 204        64.0       --                                               Oil phase                                                                     Permethrin        25.0       391                                              Hexadecan-1-ol    6.0        141                                              Emulsifiers/dispersing agents                                                 Tegoplant EM11    1.0                                                         Sodium diisopropyl naphthalene                                                                  4.0                                                         sulfonate e.g. Aerosol OS                                                     [Cyanamid G.B. Ltd.]                                                          ______________________________________                                    

EXAMPLE 9

A ULV herbicide formulation (containing a water soluble herbicide).

    ______________________________________                                                      % mass/mass                                                                            Rel. molar mass                                        ______________________________________                                        Oil phase                                                                     Solvesso 200    10.0       163.0                                              Hexadecan-1-ol  3.0        242                                                Emulsifiers                                                                   Span 80         6.6                                                           Tween 80        3.4                                                           Aqueous phase                                                                 Water           40.0       18                                                 Glyphosate-     36.9                                                          mono isopropylammonium                                                        ______________________________________                                    

This formulation may be modified for other water-miscible activeingredients, for example the components of Bordeaux mixture orquaternary ammonium compounds.

EXAMPLE 10

An LV synergist spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Piperonyl butoxide                                                                              64.0       338                                              Hexadecan-1-ol    7.5        242                                              Emulsifiers                                                                   NPE 80                       7.0                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Propan-2-ol       21.5                                                        ______________________________________                                    

EXAMPLE 11

An LV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Solvesso 150      8.8        144                                              Hexadecan-1-ol    1.2        242                                              Emulsifiers                                                                   SMO                          0.3                                              PMO                          0.9                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Dimethoate        80.0                                                        Propan-2-ol       8.8                                                         ______________________________________                                    

EXAMPLE 12

A wettable powder insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Solvesso 150      25.0       144                                              Hexadecan-1-ol    5.0        242                                              Emulsifiers                                                                   SDNS                         7.5                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Diflubenzuron     25.0                                                        Mineral silicates 37.5                                                        ______________________________________                                    

EXAMPLE 13

A flowable fungicide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Solvesso 150      15.0       144                                              Hexadecan-1-ol    6.0        242                                              Emulsifiers                                                                   SMO                          1.4                                              PMO                          3.6                                              Aqueous phase                                                                 Water (pH = 13)   48.9       18                                               Sodium hydroxide  0.1                                                         1,2 propandiol    4.0                                                         Inert/Water Soluble ingredients                                               Thiabendazole     20.0                                                        Xanthan gum       0.5                                                         Mineral silicates 0.5                                                         ______________________________________                                    

EXAMPLE 14

An LV insecticide spray

    ______________________________________                                                    % mass/mass                                                                            Rel. molar mass                                          ______________________________________                                        Oil phase                                                                     Exxate 700    5.0        158                                                  Hexadecan-1-ol                                                                              4.0        242                                                  Emulsifiers                                                                   OE/PGO        2.4                                                             Aqueous phase none                                                            ______________________________________                                    

EXAMPLE 15

A ULV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Cypermethrin      10.0       416                                              Solvesso 150      40.0       144                                              Hexadecan-1-ol    4.0        242                                              Emulsifiers                                                                   OE/PGO            2.0                                                         Aqueous phase                                                                 Water             44.0                                                        Inert/Water Soluble ingredients                                                                 none                                                        ______________________________________                                    

EXAMPLE 16

A ULV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Methoprene        28.0       311                                              Solvesso 150      28.0       144                                              Hexadecan-1-ol    7.0        242                                              Emulsifiers                                                                   NPE                          4.0                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Propan-2-ol       33.0                                                        ______________________________________                                    

EXAMPLE 17

An LV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Amitraz           18.0       293                                              Solvesso 150      36.0       144                                              1-Hexadecylamine  16.3       242                                              Emulsifiers                                                                   SMO                          1.8                                              PMO                          4.5                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Propan-2-ol       23.4                                                        ______________________________________                                    

EXAMPLE 18

An LV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Malathion         65.0       330                                              Hexadecan-1-ol    7.5        242                                              Emulsifiers                                                                   SMO                          2.0                                              PMO                          5.0                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Propan-2-ol       20.5                                                        ______________________________________                                    

EXAMPLE 19

An LV insecticide spray

    ______________________________________                                                        % mass/mass                                                                            Rel. molar mass                                      ______________________________________                                        Oil phase                                                                     Fenitrothion      65.0       277                                              Hexadecan-1-ol    4.0        242                                              Emulsifiers                                                                   SMO                          2.0                                              PMO                          5.0                                              Aqueous phase     none                                                        Inert/Water Soluble ingredients                                               Propan-2-ol       24.0                                                        ______________________________________                                    

COMPARATIVE EXAMPLE A (A ULV INSECTICIDE FORMULATION).

    ______________________________________                                        Oil phase        % mass/mass                                                                              Rel. molar mass                                   ______________________________________                                        Permethrin       10.8       391                                               S-Bioallethrin   1.7        302                                               Piperonyl Butoxide                                                                             12.3       338                                               Mineral Oil      20.0       296                                               Kerosene         41.7       170                                               Hexadecan-1-ol   1.0        242                                               Nonylphenol ethylene oxide                                                                     8.2        638                                               condensate**                                                                  Calcium dodecyl  4.3        394                                               benzenesulfonate**                                                            ______________________________________                                         **emulsifiers assumed to partition mostly into aqueous phase on dilution.

Diluted 1+9 with water for application and the average relative molarmass of oil phase=254. The molar solubility ratio (moles oil phase/moleslong chain alcohol)=10.0.

Model prediction ratio (mass of oil phase/mass of alkanol) of aformulation within the scope of the invention:

Maximum ratio with an evaporation rate (L) of 15 units=33.0, with an Lof 10 units=20.4, and with an L of 5 units=9.0. The above formulationhad the ratio (moles of oil phase/moles long chain alcohol)=86, and wastherefore outside the scope of the invention. The ratio (moles ofwater/moles of alkanol)=12100 on dilution. Observed average evaporationrate=20 units

* Example 1 of GB-A-2 095 109.

ANALYSIS OF FORMULATIONS

The analysis of a given formulation to determine whether it satisfiesthe formula above is illustrated as follows:

Analysis of Example 1A:

The permethrin, S-bioallethrin, piperonyl butoxide, odorless kerosene,emulsifiers and antifoam agent constitute the oil phase and each one ofthese components may be taken in turn at the level in the formulationand diluted in water (%1+9). One could observe that the permethrin,S-bioallethrin, odorless kerosene and piperonyl butoxide were notmiscible with water at this dilution level, e.g. permethrin has asolubility of 0.2 mg/l of water at 30° C. These components thereforeconstitute the oil phase. The emulsifiers would be miscible with watergiving a clear solution upon dilution. Of the antifoam agent, (0.1%) 30%of this would not be soluble in the oil phase or the water and wouldsimply be classed as an inert ingredient. The oil phase would then beconstituted in the proportions in the formulation. The solubility limitof hexadecan-1-ol was determined by preparing a series of mixtures andnoting the maximum composition at which all the hexadecan-1-ol remainedin solution at 27° C. after a period of 24 hours. A mixture containing8.7% mass/mass of hexadecan-1-ol was the composition in this case. Therelative molar mass of the oil phase was also required and this wascalculated as follows from the relative molar mass of each component andthe proportions in the oil phase: ##EQU6##

The relative molar mass of hexadecan-1-ol was 242. The molar solubilityratio (moles oil phase/moles film forming agent)

    =((100-8.7)/271)/(8.7/242)=9.37

This provided all the variables to use in the right hand side of theequation. With L=15, the predicted maximum ratio of mass oil phase offilm forming agent was 27. The above formulation had a mass oil phase tofilm forming agent of 10.8 (33.45/3). Therefore, it was clearly withinthe scope of the formula. The level of hexadecan-1-ol could be reducedto 1.21% with the same level of oil phase and still remained with thescope of the formula. However, a formulation with 1.0% hexadecan-1-olwould be outside the scope of the formula.

Analysis of Example 4A:

This formulation contained permethrin, 4-methylpentan-2-one,hexadecan-1-ol, emulsifiers and propan-2-ol and the formulation wasdiluted 1+9 parts with water for use.

All the components given could potentially constitute the oil phase,once diluted. Propan-2-ol was completely miscible with water over allcompositions and the emulsifiers were also water miscible when diluted.The permethrin and 4-methyl pentan-2-one were not completely misciblewith water when diluted at this level and the oil phase thereforeconsisted of permethrin and 4-methyl-pentan-2-one. The solubility ofhexadecan-1-ol was determined in this mixture as described above at 27°C. The solubility of hexadecan-1-ol in the mixture of permethrin and4-methylpentan-2-one was 16.0% mass/mass and the relative molar mass ofthe oil phase was calculated from the relative molar mass of thecomponents and their proportion in the oil phase: ##EQU7##

The relative molar mass of hexadecan-1-ol was 242 and the molarsolubility ratio (moles oil phase/moles film forming agent)

    =([100-16.11)/149)/(16/242)=8.5

This gave all the variables to be used on the right hand side of theequation. With L=15, then the maximum ratio of oil phase tohexadecan-1-ol was 66. The above formulation had a mass ratio of oilphase to film-forming agent of 9.5 and was well within the scope of theformula. The level of hexadecan-1-ol could be reduced to 0.87% whilemaintaining the oil phase levels constant and still remained within thescope of the formula.

Analysis of Example 4B:

It will be observed that this formulation was the same as that given asExample 4A except that the formulation was diluted 1+29 parts withwater. Permethrin was the only component within the formulation that wasimmiscible with water at this level of dilution. 0.32 g of4-methyl-pentan-2-one dissolved completely in 29 g of water and thepermethrin in this example constituted the oil phase. The solubility ofhexadecan-1-ol in permethrin was 1.8% w/w which gave a molar solubilityratio of 33.7.

With L=15, the maximum ratio of oil phase to film-forming agent was 99.At this dilution level, the level of hexadecan-1-ol in the formulationcould be reduced to 0.4% and still remained within the scope of theformula. This also provided an example of where the evaporation rate ofa formulation was improved as a result of further dilution because ofadditional partitioning of one of the oil phase components in theaqueous phase. There was less oil phase for the film forming agent todissolve in, thus more was available to form a film at the surface ofthe droplet.

Analysis of Example 13:

This formulation contained Solvesso 150, hexadecan-1-ol, emulsifiers,water, sodium hydroxide, 1,2-propandiol, thiabendazole, xanthan gum, andmineral silicates which was a fairly complex formulation. The activeingredient was not particularly soluble in the aqueous or oil phase anda fine particulate suspension of the active ingredient was thereforemade. The formulation also contained a thickening agent to aid thesuspension of the particulates. This was a high molecular weightpolysaccharide that was insoluble in the oil phase and it can beregarded as an inert substance. The formulation also contained poweredmineral silicates of low bulk density to prevent the formulation from"caking" (particles sticking together). The 1,2-propandiol was added toprevent freezing and was completely water miscible. The sodium hydroxidewas added to buffer the formulation at around a pH of 13 and was watersoluble. The oil phase consisted of only Solvesso 150 with possibly asmall amount of thiabendazole dissolved in it.

The solubility of hexadecan-1-ol in Solvesso 150 was 23.5% mass/mass andthe relative molar mass of Solvesso 150 was 144. The molar solubilitywas 5.5. The right hand side of the formula with L=15, gave a ratio(mass of oil phase/mass of film forming agent)=35. The formulation had amass ratio of 2.5 and was clearly within the scope of the formula. Thelevel of hexadecan-1-ol could be reduced substantially and theformulation remained within the scope of the formula.

                                      TABLE 1                                     __________________________________________________________________________    Example No:                                                                              1A  1B  2   3   4A  4B  5                                          __________________________________________________________________________    Dilution for                                                                             9   9   19  29  9   29  0                                          appln. 1 + n                                                                  Av. Rel. Molar                                                                           271 271 162 164 149 391 173                                        mass of oil phase                                                             Mass solubility                                                                          8.7 8.7 16.5                                                                              16.5                                                                              16.0                                                                              1.8 7.5                                        Molar solubility                                                                         9.4 9.4 7.6 7.5 8.5 33.7                                                                              17.2                                       ratio                                                                         Maximum ratio                                                                 calcd. for L                                                                  L = 15     27  27  47  45  66  99  145                                        L = 10     17  17  29  28  41  61  90                                         L = 5      7   7   13  12  18  27  40                                         Mass of oil                                                                              10.8                                                                              10.5                                                                              6.2 4.6 9.5 9.5 8.6                                        Mass of film-former                                                           L measured 3.8 3.8 4.0 4.5 5.0 4.2 3.8                                        Moles (water)                                                                            4318                                                                              5278                                                                              5278                                                                              5685                                                                              2016                                                                              6498                                                                              663                                        Moles (film-former)                                                           __________________________________________________________________________    Example No.                                                                              6   7   8   9   10  11  12                                         __________________________________________________________________________    Dilution for                                                                             0   14  39  39  39  29  39                                         appln. 1 + n                                                                  Av. Rel. Molar                                                                           258 199 391 153 338 144 144                                        mass of oil phase                                                             Mass solubility                                                                          4.0 9.0 1.8 12.5                                                                              5.5 23.5                                                                              23.5                                       Molar solubility                                                                         25.1                                                                              12.2                                                                              33.7                                                                              10.4                                                                              12.3                                                                              5.5 5.5                                        ratio                                                                         Maximum ratio                                                                 calcd. for L                                                                  L = 15     116 68  99  75  28  35  35                                         L = 10     72  42  61  47  17  22  22                                         L = 5      32  19  99  21  8   10  10                                         Mass of oil                                                                              2.5 9.6 13.3                                                                              8.5 8.5 5.0 5.0                                        Mass of film-former                                                           L measured 4.8 4.7 5.3 3.8 5.3 7.5 7.0                                        Moles (water)                                                                            435 6520                                                                              6691                                                                              32490                                                                             6991                                                                              11089                                                                             10487                                      Moles (film-former)                                                           __________________________________________________________________________    Example No.                                                                              13  14  15  16  17  18  19                                         __________________________________________________________________________    Dilution for                                                                             49  19  19  19  19  19  19                                         appln. 1 + n                                                                  Av. Rel. Molar                                                                           144 158 166 197 173 330 277                                        mass of oil phase                                                             Mass solubility                                                                          23.5                                                                              16.5                                                                              15.0                                                                              18.5                                                                              20.1                                                                              1.9 0.8                                        Molar solubility                                                                         5.5 7.8 8.2 5.4 5.5 37.8                                                                              108                                        ratio                                                                         Maximum ratio                                                                 calcd. for L                                                                  L = 15     35  51  52  20  26  157 1038                                       L = 10     22  32  32  13  16  97  643                                        L = 5      10  14  14  6   7   43  284                                        Mass of oil                                                                              2.5 1.3 12.5                                                                              8.0 3.3 8.7 16.3                                       Mass of film-former                                                           L measured 7.5 7.3 4.7 7.8 4.5 6.4 5.1                                        Moles (water)                                                                            11089                                                                             9747                                                                              6534                                                                              3649                                                                              1567                                                                              3402                                                                              6386                                       Moles (film-former)                                                           __________________________________________________________________________

EXAMPLE 20

Formulations

    ______________________________________                                        Ingredients         % w/w                                                     ______________________________________                                        chlorpyrifos methyl 19.15                                                     solvesso 150        19.15                                                     water (deionised)   51.40                                                     emulsifiers         2.00                                                      Deltamethrin (20% SC)                                                                             5.20                                                      ______________________________________                                    

The deltamethrin (20% SC) contained deltamethrin (20%) in water withsurfactant, thickening agents and biological preservative. The oil phasewas prepared by dissolving cetyl alcohol in a solution of chlorpyrifosmethyl in Solvesso 150 at a temperature up to 50° C. The emulsifierswere added to the water at 60° C. and the resultant aqueous solution wascooled to 50° C. (aqueous phase). The oil phase was added to the aqueousphase at 50° C. with vigorous mixing and the resultant emulsion wascooled to 20° C. A 20% aqueous suspension of deltamethrin was added withstirring at 20°-25° C.

EXAMPLE 21

Stability Testing

Tests were carried out on the stability of active ingredients in aformulation of the present invention (A) and in a two phase formulationthat did not contain stabilizer (B).

Formulation A Results

A chlorpyrifos methyl/deltamethrin formulation with film-forming agentwas prepared in a similar manner to Example 20 above.

Typical Stability Data: chlorpyrifos methyl (CPMe) tests (figures±10%)

    ______________________________________                                        Time in months (M)                                                                          25° C.                                                                             38° C.                                                                         50° C.                               Initial       100         100     100                                         3 M or 4 M    101         103     103                                         6 M           102         100     103                                         12 M          101          94     101                                         Typical Stability Data: Deltamethrin (DLTM)                                   Time in months (M)                                                                          25° C.                                                                             38° C.                                                                         50° C.                               Initial       100         100     100                                         3 M or 4 M     96          99      98                                         6 M            97         103     103                                         12 M           98          94      76                                         ______________________________________                                    

Formulations B--results

A chlorpyrifos methyl/Deltamethrin Formulation without film formingagent.

    ______________________________________                                        Typical Stability Data: CPME                                                  Time in months (M)                                                                          25° C.                                                                             38° C.                                                                         50° C.                               Initial       100         100     100                                         3 M           112         106      71                                         Typical Stability Data: DLTM                                                  Time in months (M)                                                                          25° C.                                                                             38° C.                                                                         50° C.                               Initial       100         100     100                                         3 M            75          75      16                                         ______________________________________                                    

The results show formulations (B) without film forming agent arerelatively unstable.

EXAMPLE 22

Biological Testing

Protocol: An appropriately water-diluted formulation was sprayed on to400 tons of grain at Wail, Victoria. It was applied to the grain streamduring turning at one liter of spray per ton. Treated grain was sampledat intervals by a vacuum probe and bioassays were conducted by holding100 adult insects on 150 g or 300 g of grain. After 3 weeks ofincubation at 25° C. and 55-60% relative humidity, the insects weresieved off and mortality counted. The grain was further sieved at 7, 9,and 11 weeks to remove and mortality count adult progeny.

    ______________________________________                                        (1) 0.24; 4.9 mg/kg deltamethrin; chlorpyrifos-methyl                                   Months                                                                        of post-          Progeny  Progeny                                  Insects   treatment                                                                              %        numbers  suppression                              tested    storage  Mortality                                                                              living                                                                              dead %                                      ______________________________________                                        Sitophilus                                                                              0        100      0     4    99.8                                   oryzae    1.5      100      0     0    100                                              3        100      0     0    100                                              4.5      100      0     0    100                                              6        100      0     0    100                                              9        100      0     0    100                                    Rhyzopertha                                                                             0        100      0     0    100                                    dominica  1.5      100      0     0    100                                              3        100      0     0    100                                              4.5      100      0     0    100                                              6        100      0     0    100                                              9        100      0     0    100                                    Tribolium 0        100      0     0    100                                    castaneum 1.5      100      0     1    99.7                                             3        100      0     0    100                                              4.5      100      0     1    99.5                                             6        100      0     4    99.0                                             9        100      0     0    100                                    Queensland                                                                              0        100      0     0    100                                    Tribolium 1.5      100      0     2    97                                     castaneum 3        99       0     0    100                                              4.5      99       0     1    99.7                                             6        100      0     4    99.0                                             9        95       0     0    100                                    ______________________________________                                    

Results show good control of insect pests for post-treatment storage upto 9 months,

Various modifications of the compositions and method of the inventionmay be made without departing from the spirit or scope thereof and it isto be understood that the invention is intended to be limited only asdefined in the appended claims.

What we claim is:
 1. Formulation suitable for spraying or for dilutionwith water to form a sprayable preparation, the formulation comprisingan active ingredient, optionally a carrier or solvent for the activeingredient, an emulsifier and an evaporation retardant, characterized inthat the formulation satisfies the following Formula: ##EQU8## where Lis less than or equal to 15, A: 700376, B=-1.51, C=0.8472, H_(oil) isthe weighted average relative molar mass of the oil phase,M_(retardant)is the weighted average relative molar mass of the retardant, and##EQU9## where Y is the molar solubility ratio of the formulation,defined as the minimum number of moles of the oil phase which willdissolve the retardant, divided by the number of moles of retardant,provided that, in the Formula above, any solvent which has no liquidphase at 27° C. at atmospheric pressure is excluded.
 2. A Formulationaccording to claim 1 wherein L is less than
 10. 3. A formulationaccording to claim 2 wherein L is less than
 5. 4. A Formulationaccording claim 1 wherein the active ingredient is a pesticide orherbicide.
 5. A formulation according to claim 4 wherein the activeingredient is a pyrethroid.
 6. A formulation according to claim 1 wherein the solvent has a relative molar mass of less than
 200. 7. Aformulation according to claim 6 herein the solvent comprises kerosene,odorless kerosene, mineral oil, heptyl acetate, 4 -methylpentan-2-one orbutane.
 8. A formulation according claim 1 wherein the formulation is an-ultra low volume concentrate and the proportion of the oil phase isbetween 8% and 30% by mass before dilution for use.
 9. A formulationaccording to claim 1 wherein the formulation is a wettable power.
 10. Aformulation according to claim 1 wherein the evaporation retardant ishexadecan-1-ol or a mixture of hexadecan-1-ol and octadecan-1-ol.
 11. Aformulation according claim 10 which is to be diluted before use andwhich comprises from 1.0 to 7.5% evaporation retardant by mass.
 12. Aformulation according to claim 1 wherein the emulsifier is a non-ioniccompound with an HLB value of 8-18, or a mixture of non-ionic compounds,the mixture having a weighted average HLB value of 8-18.
 13. Aformulation according to claim 1 which is diluted and ready for use andwhich comprises 0.0 to 3.2% oil phase by weight.
 14. A formulationaccording to claim 13 which is diluted and ready for use and whichcomprises 0.25 to 1.5% oil phase by weight.
 15. A method of combatinginsect or acarine pests or unwanted plants by spraying a formulation ofclaim 1, optionally diluted with water, wherein the formulationcomprises an insecticide, acaricide or herbicide.
 16. A pesticidalformulation comprising a two phase formulation, the first phase of whichis water immiscible and comprises a first active ingredient, astabilizer, and optionally an emulsifier or wetting or dispersing agent,and a carrier or solvent for the active ingredient; and a second phaseimmiscible with the first phase which is water and comprises a secondactive ingredient and optionally an emulsifier or wetting or dispersingagent and a carrier or solvent for the second active ingredient, whereinthe first phase of the formulation satisfies the formula: ##EQU10##where L is less than or equal to 15, A=700376, B=-1.51. C=0.8472 M_(oil)is the weighted average relative molar mass of the oil phaseM_(stabilizer) is the average molar mass of the stabilizer, and##EQU11## where Y is the molar solubility ratio of the formulation,defined as the minimum number of moles of oil phase which will dissolvethe stabilizer, divided by the number of moles of stabilizer, providedthat, in the formula above, any solvent which has no liquid phase at 27°C. at atmosphere pressure is excluded.
 17. A pesticidal formulationaccording to claim 16 wherein L is less than
 5. 18. A pesticidalformulation according to claim 16 wherein the stabilizer is a C₁₆₋₂₀saturated alkanol, or C₁₆₋₁₈ saturated amine.